摘要：This paper aims to assess the efficiency of carrot juice lactic fermentation in the presence of the addition of cysteine and leucine. Lactic fermentation causes an increase in the nutritional value of fruit and vegetable juices, because the enzyme lactic bacteria can predigests the macromolecular compounds intensifying the digestibility and nutrient content. The indicators monitored were pH, reducing sugars and the count of Lactobacillus acidophilus. Materials used were carrot juice (control sample M), carrot juice with cysteine (C) and with leucine (L). All samples were fermented in the presence of Lb.Acidophilus LA-5(0.2g/l), in anaerobic conditions at 37deg.C. The count of Lactobacillus acidophilus was determined by plate count method using Man–Rogosa-Sharpe agar. The results were expressed as CFU/ml juice. Was monitored the evolution of parameters that characterize the lactic fermentation in control sample and the samples with the addition of cysteine and leucine. The results highlight the role of the addition of cysteine in the sample of juice, because the yield is superior to the other samples, the degree of metabolism of carbohydrates was the biggest after 96 hours 1.34g/100ml, which correlates with the lowest pH and high cell viability Lb.Acidophilus LA-5. For describing the time evolution of the process of lactic fermentation was used a polynomial function that faithfully reproduce the metabolism of carbohydrates. The addition of leucine did not affect the lactic fermentation the parameters analyzed were similar to those of the control sample
